Changing Substrate

[bettafishlover86]

I have a few plants, a male betta, and 6 otocinclus catfish in my 29-gallon aquarium. My current substrate is gravel. I want to get some kuhli loaches but I am worried the gravel will be too sharp for them. I am planning on switching to sand. I have had the tank for 1 year and it is fully cycled . Will changing the substrate restart the cycle?

 

[Uberhoust]

I have changed my substrate many times now, I haven't had issues with my cycle during these changes. But I have a lot of plants, light fish population, and slightly oversized filters. The one area of concern I would have are your oto cats, they like an established tank with biofilm over the surfaces. Changing your substrate might have a very negative impact on the amount of biofilm available with them. I haven't raised Otos, so don't know really how sensitive they are.

 

[ella777]

I have changed my substrate many times now, I haven't had issues with my cycle during these changes. But I have a lot of plants, light fish population, and slightly oversized filters. The one area of concern I would have are your oto cats, they like an established tank with biofilm over the surfaces. Changing your substrate might have a very negative impact on the amount of biofilm available with them. I haven't raised Otos, so don't know really how sensitive they are.

What's biofilm?

 

[Beastije]

From my perspective, releasing the ammonia traped in the substrate will negatively impact the tank. I would do a less standard approach, taking the fish out to a bucket, maybe even disconnecting the filter. Changing the gravel, leaving some of the mulm. Doing 90% water change. Letting it sit for few hours. Return the filter, let it run for few hours, maybe do other change, check ammonia levels and only after then returning the fish
If you were changing sand, would be easier, using a hose to suck the sand with the ammonia . But with gravel you will most likely need to use a dustbin pan or smth. And that means releasing the bad stuff into the water column.
I hope someone else who is more qualified will propose an easier approach

 

[Uberhoust]

To keep it simple the biofilm is like a coating of bacteria, algae, and sometimes protozoans that tends to eventually coat everything in the tank. A number of fish, and other creatures depend on this film for a portion of their diet. Otos are one of these fish.

In regards to the substrate changes, I was assuming the fish would be removed from the tank and placed in buckets. I also cover the buckets so that they are darker, reduces the stress on the fish. My process is as follows (assuming sand pre-rinsed):

1. Remove fish and plants and decorations to buckets or another tank if you have one. (do not clean the decorations or rocks at this time)
2. Turn off filter (Do not clean)
3. Drain as much water, and waste as possible.
4. Remove all the gravel
5. Remove remaining water
6. Place sand, decorations, and plants in tank
7. Treat and fill tank with water
8. Run filter for a day
9. About 24 hours later rinse out filter (In my experience a freshly rinsed filter doesn't do as good of a job removing dust from the new sand and gravel)

After removing the fish I try to work as fast as I can to get to where you put the fish back in. You will have some biofilm on the plants and decorations, but with 5 otos I don't know if that will be enough. Because you need the biofilm I wouldn't wash any of the decorations. Any ammonia associated with the gravel will be removed with the original water.

 

[bettafishlover86]

than

To keep it simple the biofilm is like a coating of bacteria, algae, and sometimes protozoans that tends to eventually coat everything in the tank. A number of fish, and other creatures depend on this film for a portion of their diet. Otos are one of these fish.

In regards to the substrate changes, I was assuming the fish would be removed from the tank and placed in buckets. I also cover the buckets so that they are darker, reduces the stress on the fish. My process is as follows (assuming sand pre-rinsed):

1. Remove fish and plants and decorations to buckets or another tank if you have one. (do not clean the decorations or rocks at this time)
2. Turn off filter (Do not clean)
3. Drain as much water, and waste as possible.
4. Remove all the gravel
5. Remove remaining water
6. Place sand, decorations, and plants in tank
7. Treat and fill tank with water
8. Run filter for a day
9. About 24 hours later rinse out filter (In my experience a freshly rinsed filter doesn't do as good of a job removing dust from the new sand and gravel)

After removing the fish I try to work as fast as I can to get to where you put the fish back in. You will have some biofilm on the plants and decorations, but with 5 otos I don't know if that will be enough. Because you need the biofilm I wouldn't wash any of the decorations. Any ammonia associated with the gravel will be removed with the original water.

thanks